Fairphone 4 Camera test

For scoring and analysis, SBMARK engineers capture and evaluate more than 2,600 test images in both controlled laboratory environments and natural outdoor, indoor and low-light scenes, using the camera’s default settings. The photographic protocol is designed to take into account the main use cases and is based on typical shooting scenarios, such as portraits, family photos and landscapes. Assessment is done by visually inspecting images Cons a natural scene reference and making objective measurements on graphical images captured in the lab under various lighting conditions from 1 to 1,000+ lux and color temperatures from 2,300K to 6,500K.

Exposure and color are the key attributes for technically good images. For exposure, the main attribute evaluated is the brightness of the main subject in various use cases such as landscape, portrait or still life. Other factors evaluated are contrast and dynamic range, eg. the ability to make details visible in both light and dark areas of the image. Repeatability is also important, as it demonstrates the camera’s ability to deliver the same rendering when shooting multiple images of the same scene.
For color, the image quality attributes analyzed are skin tone rendering, white balance, color shading, and repeatability. For the rendering of color and skin tone, we penalize unnatural colors but respect the manufacturer’s choice of the chromatic signature.

These tests analyze the performance of the ultra-wide-angle camera at different focal lengths from 12mm to 20mm. All image quality attributes are evaluated, with particular attention to artifacts such as chromatic aberrations, lens softness and distortion. The images below are an excerpt of tested scenes.

All image quality attributes are evaluated at focal lengths from about 40mm to 300mm, with a focus on texture and detail. The score is derived from a series of objective measurements in the laboratory and from the perceptual analysis of real-life images.

SBMARK engineers capture and evaluate more than 2.5 hours of video in controlled laboratory environments and natural scenes in low light conditions, indoors and outdoors, using the camera’s default settings. The assessment consists of visually inspecting natural videos taken under various conditions and carrying out objective measurements on graphical videos recorded in the laboratory under different conditions from 1 to 1000 lux and color temperatures from 2300 to 6500 K.

Exposure tests evaluate the brightness of the main subject and the dynamic range, eg. the ability to make details visible in both light and dark areas of the image. The stability and temporal adaptation of exposure are also analyzed.
Image quality color analysis examines color rendition, skin tone rendition, white balance, color shading, white balance stability and its adaptation when the light changes.

Texture tests analyze the level of detail and texture of real-life videos, as well as graphics videos recorded in the lab. Natural video recordings are evaluated visually, with particular attention to the level of detail in bright areas and dark areas. Objective measurements are performed on images of graphs taken under various conditions from 1 to 1000 lux. The charts used are the SBMARK (DMC) chart and the Dead Leaves chart.

Noise tests analyze various noise attributes such as intensity, chromaticity, grain, texture, temporal aspects on real-life video recordings and graphing videos taken in the laboratory. Natural videos are evaluated visually, with a focus on noise in dark areas and high dynamic range conditions. Objective measurements are performed on card videos recorded under various conditions from 1 to 1000 lux. The graph used is the SBMARK visual noise graph.

Artifacts are evaluated with MTF and ring measurements on the SFR graph in the laboratory, as well as frame rate measurements using the Universal Timer LED. Natural videos are visually evaluated with particular attention to artifacts such as aliasing, quantization, locking, and toning, among others. The more severe and frequent the artifact, the greater the point deduction from the score. The main artifacts and the corresponding point loss are listed below.